Hydraulic pump with solid-state actuator

ABSTRACT

A hydraulic pump includes a port and a piston assembly fluidically coupled to the port. The piston assembly includes a piston and a solid-state actuator, where a shape change of the solid-state actuator is induced when a field is applied to the solid-state actuator, and where alternating shape changes of the solid-state actuator provide reciprocating movement to the piston.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/451,302, which was filed Mar. 10, 2011 and is hereby incorporated byreference in its entirety.

BACKGROUND

The present disclosure relates to providing hydraulic power and, moreparticularly, to providing hydraulic power with a solid-state hydraulicpump that utilizes a solid-state actuator to drive a piston and therebyprovide the force for volumetric displacement of fluid in a pistonchamber.

In general, conventional hydraulic pumps may include a piston, acylinder, and a pump chamber. The piston may reciprocate within thecylinder to compress or expand the volume of a pump chamber. One or morevalves may provide for opening an inlet and an outlet of the pumpchamber to allow fluid into the pump chamber in an expansion stroke ofthe piston and fluid out of the chamber in the compression stroke of thepiston. A sealing member may be provided between the cylinder and thepiston to prevent the fluid being pumped from leaking into the gapbetween the piston and the cylinder.

Conventional pumps often rely on a source of mechanical power such as amotor or an engine to provide the reciprocating movement to the piston.These conventional pumps have numerous rotating parts and have inherentinefficiencies. These conventional pumps also have a tendency to heatthe fluids that they pump. These conventional pumps also need a largediameter for the windings and tend to be an inductive electrical load.

It is desirable to provide a pump that has a reduced number of rotatingparts, exhibits higher efficiencies, and has a lower tendency to heatthe fluids that it pumps.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features.

FIG. 1 is an illustration of a hydraulic pump, in accordance withcertain embodiments of the present disclosure.

FIG. 2 is an illustration of a hydraulic pump, in accordance withcertain embodiments of the present disclosure.

FIG. 3 is an illustration of a hydraulic pump system used to facilitateheat transfer, in accordance with certain embodiments of the presentdisclosure.

FIG. 4 is an illustration of a heat pump system, in accordance withcertain embodiments of the present disclosure.

FIGS. 5A, 5B, and 5C are partial illustrations of a completely sealedhydraulic pump, in accordance with certain embodiments of the presentdisclosure.

While embodiments of this disclosure have been depicted and describedand are defined by reference to exemplary embodiments of the disclosure,such references do not imply a limitation on the disclosure, and no suchlimitation is to be inferred. The subject matter disclosed is capable ofconsiderable modification, alteration, and equivalents in form andfunction, as will occur to those skilled in the pertinent art and havingthe benefit of this disclosure. The depicted and described embodimentsof this disclosure are examples only and are not exhaustive of the scopeof the disclosure.

DETAILED DESCRIPTION

The present disclosure relates to providing hydraulic power and, moreparticularly, to providing hydraulic power with a solid-state hydraulicpump that utilizes a solid-state actuator to drive a piston and therebyprovide the force for volumetric displacement of fluid in a pistonchamber.

Illustrative embodiments of the present disclosure are described indetail herein. In the interest of clarity, not all features of an actualimplementation may be described in this specification. It will of coursebe appreciated that in the development of any such actual embodiment,numerous implementation-specific decisions must be made to achieve thespecific implementation goals, which will vary from one implementationto another. Moreover, it will be appreciated that such a developmenteffort might be complex and time-consuming, but would nevertheless be aroutine undertaking for those of ordinary skill in the art having thebenefit of the present disclosure.

To facilitate a better understanding of the present disclosure, thefollowing examples of certain embodiments are given. In no way shouldthe following examples be read to limit, or define, the scope of thedisclosure. Embodiments of the present disclosure may be applicable tohorizontal, vertical, deviated, or otherwise nonlinear wellbores in anytype of subterranean formation. Embodiments may be applicable toinjection wells as well as production wells, including hydrocarbonwells.

In certain embodiments according to the present disclosure, asolid-state material, such as a magnetostrictive material, may be usedto provide movement to a piston that is fluidically coupled to a port.The port may include an inlet and/or an outlet. In certain embodiments,the solid-state material, piston, and port may be within a hydraulicpump. Magnetostrictive materials have the property that, when a magneticfield is applied to the material, a strain is induced in the material,causing a change in the linear dimensions. This strain and change in thelinear dimensions of the material may cause movement to a piston withina hydraulic pump. A suitable material for the magnetostrictive materialmay be Terfenol-D, available from Etrema Products, Inc. Variousmaterials, e.g., iron and iron alloys such as Terfenol, may providesuitable magnetostrictive and giant magnetostrictive responses. Amagnetic field may be applied to these materials, e.g., by applying anelectric current to a coil surrounding the material or to a loopanywhere else in the magnetic circuit.

FIG. 1 is an illustration of one example hydraulic pump comprising asolid-state material to actuate the hydraulic pump, in accordance withcertain embodiments of the present disclosure. As shown in FIG. 1, ahydraulic pump 100 may include body 101, a solid-state actuator 105, acoil 110, a pump piston 115 in a cylinder 116 to compress or expand thevolume of a pump chamber 117, a seal 120, phase balancing electronics125, a power source 130, an inlet check valve 135, an outlet check valve140, and ports which may include a low-pressure inlet 145 and ahigh-pressure outlet 150.

The solid-state actuator 105 may comprise a piezoelectric ormagnetostrictive material. The solid-state actuator 105 may be anysuitable piezoelectric or magnetostrictive materials include anypiezoceramic, piezoelectric, electrostrictive, ferroelectric, relaxorferroelectric, or magnetostrictive material that that can be driven byan electrical or magnetic input and that provides a mechanical output inthe form of a force or motion. When an electric or magnetic field isapplied to such materials, the materials change shape in response to theapplied field. These materials also usually respond to mechanical forceor motion by generating an electric field which produces a voltageacross its electrical connections, e.g., across electrodes, or amagnetic field which in turn may produce voltage across a conductorcoiled around the materials.

For purposes of the present disclosure, each solid-state actuator 105 isconsidered to have one or more electrical or magnetic connections andone or more mechanical connections. Each connection may be considered tobe an input or an output or both, depending on whether the actuator isbeing used at the time to convert electrical energy into force or motionor to convert force or motion into electrical energy. As a result, thesolid-state actuator 105 comprising such materials may be used as anactuator and as a sensor. The solid-state actuator 105 may comprise thepiezoelectric or magnetostrictive material in the form of a stack, aseries of thin plates stacked and wired electrically in parallel. Thepiezoelectric or magnetostrictive material may also possess apolycrystalline, single crystal, or amorphous structure.

As shown in FIG. 1, the coil 110 may be coiled around the solid-stateactuator 105. The coil 110 may include a insulated conductor and may bein electrical connection with the power source 130. In certainembodiments, as shown in FIG. 1, the balancing electronics 125 may alsobe in electrical connection with the power source 130 and the coil 110.In certain embodiments, the balancing electronics 125 may include acapacitor. In other embodiments, the balancing electronics 125 mayinclude an inductor. In certain embodiments, the balancing electronics125 may be used to balance the capacitance of the solid-state actuator105. In certain embodiments, the balancing electronics 125 may be usedto create an electrical resonance. In certain embodiments, theelectrical resonance is near the mechanical resonance of the system.

In certain embodiments, a shape change in the solid-state actuator 105may be induced by applying and/or varying a voltage across the coil 110.The shape change of the piezoelectric or magnetostrictive materials maybe controlled by the application of electric or magnetic fields. Itshould be appreciated that the shape may be controlled in various waysin various embodiments, for example, by using alternative means to varya magnetic field, such as with a permanent magnet or electromagnet.

In one non-limiting example, a shape change or strain of 0.5% may occuralong the long axis of the stack. It should be understood that the shapechange or strain may be greater or less than 0.5% with variousembodiments. In some embodiments, a small strain such as 0.5% maydisplace the cross-sectional area of the stack resulting in a net volumechange when measured along the primary stack axis. Such shape change maybe used to pressurize and pump a fluid in certain embodiments.

In certain embodiments, the hydraulic pump 100 may use the solid-stateactuator 105 to provide hydraulic pressure. As shown in FIG. 1, thehydraulic pump 100 may comprise the piston 115. The shape changedinduced in the solid-state actuator 105 may move the piston up and down,forcing fluid flow from the low-pressure inlet 145 to the high-pressureoutlet 150.

The hydraulic pump 100 may further include the inlet check valve 135 andthe outlet check valve 140. In some embodiments, the inlet check valve135 and the outlet check valve 140 may rectify the flow and create asteady flow passage from the low-pressure inlet 145 to the high-pressureoutlet 150. In certain embodiments, the inlet check valve 135 and theoutlet check valve 140 may comprise reed valves. In other embodiments, acompact system of valves may be needed to rectify the high frequencyreciprocating pump output. In some embodiments, simple and compactvalves may be used for this purpose. In other embodiments, separate setsof valves may act as check valves. In other embodiments, the valves maybe powered by their own solid-state actuators.

The hydraulic pump 100 may further comprise the seal 120. The seal 120may comprise a seal or a flexure. In some embodiments, the seal 120 mayform a seal around the piston 115 to ensure that no fluids come intocontact with the solid-state actuator 105. In some embodiments, the seal120 may be a ring. In some embodiments, the seal 120 may be a baffle. Insome embodiments, the seal 120 may comprise an elastomer, a plastic, ametal, a ceramic, or glass.

In some embodiments, each cycle of the pump 100 displaces an amount offluid proportional to the strain induced in the solid-state actuator105. In certain cases, the total fluid flow is proportional to the fluiddisplaced in each cycle and frequency of reciprocation. In someembodiments, frequency synchronization with the hydraulic pumps of thepresent disclosure may be guaranteed, although the phasing may not beadjustable. While valves have been employed successfully at lowerfrequencies, their frequency response limited to several thousand Hertz.

In certain embodiments, the hydraulic pumps of the present disclosuremay be capable of high-pressure operation with low flow rates. In someembodiments, effective generation of fluid power requires that thehydraulic pumps of the present disclosure operate at a substantial biaspressure. In some embodiments, for pump applications where occasionalaccess is possible, the bias pressure can be set once and then it can bemonitored and even adjusted if needed. In other embodiments, such asremote installations, adjustment may be done by different means. Inparticular, in some embodiments, an accumulator and charge system mayfunction well, but a bootstrapping bias pressurization may be anappropriate secondary method. Bootstrapping may involve additionalvalves and can be demonstrated to reliably elevate system pressure, butthe additional valves require volume and increase the number ofcomponents.

FIG. 2 is an illustration of a hydraulic pump comprising an arrangementof piston assemblies, in accordance with certain embodiments of thepresent disclosure. In certain embodiments, a hydraulic pump 200 maycomprise a pump body 101 (as shown in FIG. 1), one or more solid-stateactuators 105, one or more pistons 115 in one or more cylinders 116 tocompress or expand the volume of a pump chamber 117, one or more seals120, an inlet check valve 135, an outlet check valve 140, a low-pressureinlet 145, and a high-pressure outlet 150. In certain embodiments, thearrangement of piston assemblies may be connected in parallel in thefluid circuit. In certain embodiments, the arrangement of pistonassemblies may be electrically driven together in either parallel orseries circuit. In some embodiments, an arrangement of piston assembliesprovides for more fluid movement per cycle. An increase in fluidmovement per cycle may help to overcome the leakiness and the fluidicbacklash in the check valves. The arrangement of piston assemblies mayhave a combination of solid-state actuators that have differentelectrical loads. A solid-state actuator with a capacitive load (i.e.,piezoelectric) may be combined with a solid-state actuator with aninductive load (i.e., magnetostrictor) to create a balanced electricload. A check valve may be located between the plurality of pistonassemblies incase the different piston assemblies are not being drivenin phase. Other parts may be in between the piston assemblies, such as athermal radiator or a hydraulic accumulator.

FIG. 3 is an illustration of a hydraulic pump system that may be used tofacilitate heat transfer, in accordance with certain embodiments of thepresent disclosure. As shown in FIG. 3, a hydraulic pump 300 may passfluid through one or more radiators 310, over a circuit board 320, andthrough one or more radiators 310. Elements in the system may befluidically coupled with a conduit assembly, which may include anysuitable connections, piping, tubing, hose, etc. As depicted, thehydraulic pump system may be a closed-loop system. The fluid passed overthe circuit board 320 may absorb heat generated from the circuit board320 and radiate the heat to the environment through the one or moreradiators 310. A radiator 310 may be any suitable heat exchanger toreceive the fluid and transfer heat from the fluid passing therethroughto an exterior area adjacent to the radiator. In some embodiments, thehydraulic pump 300 may comprise each of the same components included inthe hydraulic pump 100 discussed above with respect to FIG. 1. Incertain embodiments, the hydraulic pump 300 may need less pressure butoperates at increased flow rates than conventional pumps. In otherembodiments, the hydraulic pump 300 operates with a higher efficiencythan conventional pumps. In other embodiments, the hydraulic pump 300may pass fluid through conduits created on the surface of the circuitboard 320 or on the interior of the circuit board 320.

FIG. 4 is an illustration of a heat pump system, in accordance withcertain embodiments of the present disclosure. As shown in FIG. 4, ahydraulic pump 400 may pass fluid through one or more radiators 410,through one or more expansion valves 420, and over one or moreelectronics 430. Elements in the system may be fluidically coupled witha conduit assembly, and the hydraulic pump system may be a closed-loopsystem, similar to the system of FIG. 3. In some embodiments, thehydraulic pump 400 may comprise each of the same components included inthe hydraulic pump 100 discussed above with respect to FIG. 1.

In certain embodiments, the hydraulic pump 400 may heat the fluid whenit compresses the fluid. In certain embodiments, the fluid may then becooled when it passes through the radiator 410. Additionally, in certainembodiments, the one or more expansion valves 420 may allow the fluid toexpand and further cool. The fluid may then pass over the one or moreelectronics 420 and absorb heat.

In certain embodiments, a hydraulic pump according to the presentdisclosure may be employed to charge a hydraulic accumulator. The storedhydraulic energy in the accumulator may be used for any suitabledownhole purpose. For example, the energy stored in the hydraulicaccumulator may be used to move a downstream valve, piston, sliding sidedoor, etc. Using the example of FIG. 4, the hydraulic pump 400 may becoupled to a hydraulic accumulator in lieu of the radiator 410 shown.And, instead of the downstream components 420, 430 depicted in FIG. 4,any suitable downstream components may be coupled in fluidiccommunication with upstream accumulator.

Referring again to the example of FIG. 1, the hydraulic pump 100 may beprovided with control electronics 128. The control electronics 128 mayinclude phase balancing electronics 125 or may be provided separately.Though not shown, control electronic 128 also may be provided with anyof the embodiments illustrated in FIGS. 2-4. In certain embodiments,control electronics 128 (which may include, e.g., a microprocessor) maybe configured to drive the pump to provide flow control and/or providepressure control. By way of non-limiting example, the flow control maybe provided by controlling a frequency of excitation; the pressurecontrol may be provided by controlling drive amplitude and/or bycontrolling excitation. In certain embodiments, generic digital controlmay be provided from memory and/or an outside controller to provideprogrammable arbitrary flow control and/or pressure control. In certainembodiments, digital control may be tied to temperature, pressure, flow,and/or another hydraulic pump used in a sense mode. Certain embodimentsmay be configured to have the capability to duplicate pressure and/orflow of coupled hydraulic and may thereby act as a hydraulic amplifier.

Control electronic 128 also may be provided to two or more pumps. Incertain embodiments, a plurality of pumps may be coupled and configuredto operate generally synchronously. The plurality of pumps may operatemutually out of phase to reduce ripple. A plurality of pumps or sets ofpumps may be controlled to operate one set to provide a gross setting(possibly using a physically larger, optimized pump) and other sets totrim/fine tune.

Certain embodiments may include a plurality of pumps (or sets of pumps).In certain embodiments, one pump or set of pumps may provide a grosssetting, with another providing constructive flow/pressure, and with athird that is reversed to provide destructive flow/pressure to providefor greater gross setting and additional trimming/fine tuning. Anaccumulator also may be provided to further decrease ripple. For anoptional ability to control the solid-state actuator, electronics (withone or more controller(s), memory, drive circuitry, electroniccommunication interface) can be used with a variety of sensors(including this invention) to measure pressure, flow, displacement,etc., in and/or out).

FIGS. 5A, 5B, and 5C are partial illustrations of a completely sealedhydraulic pump 500, in accordance with certain embodiments of thepresent disclosure. The hydraulic pump 500 may include certain elementspreviously disclosed herein, such as a pump body 101, a solid-stateactuator 105, a coil 110, a pump piston 115, and a port that may includea high-pressure outlet 150. However, the hydraulic pump 500 eliminatesseals in operation to eliminate the potential for system leaks inconventional pumps, which may leak either in control elements (checkvalves, solenoids, etc.) and/or between the oil volume and the exterior.Thus, the hydraulic pump 500 may be useful in a variety of applicationsincluding but not limited to uses as a jacking device, manipulating thecontrol surfaces in aircraft, boats, etc. Using any suitable method, thehydraulic section may be closed off so that the assembly would bevirtually free of moving parts, wear and contaminant creation,contaminant ingress and, properly designed immune to pressure. Invarious embodiments, suitable methods may include but not be limited tometal-to-metal-seals, weldments, compression fittings, possibly weldedclosed, etc. As depicted in FIG. 5A, the hydraulic pump 500 may includea bellows 510 coupled to the piston 115 on the outlet side for theproduction of output pressure in conjunction with actuation of thepiston 115. In certain embodiments, a spring 505 disposed between thepiston 115 and the pump body 101 may provide resiliency for the pistoncycle.

FIGS. 5B and 5C illustrate alternative embodiments of the hydraulic pump500. Instead of including the piston 115, bellows 510, and spring 505configuration, the solid-state actuator 105 may be configured todirectly actuate a compliant element 520 (FIG. 5B) or a diaphragm 525(FIG. 5C). The compliant element 520 may be any suitable compliant bodywith a shape and resilient material in the non-limiting exampledepicted, the solid-state actuator 105 is configured to directly contacta convex side of the compliant element 520. Likewise, the diaphragm 525may be any suitable bellows-type element with a shape and resilientmaterial to provide an output pressure to the outlet 150 upon actuationof the solid-state actuator 105 and a return force upon relaxation ofthe solid-state actuator 105.

While the hydraulic pump 500 is depicted by way of examples withoutlimitation in FIGS. 5A-5C as each including a single assembly for thesolid-state actuator 105, certain embodiments may include a plurality ofthe solid-state actuators 105. Any number of the solid-state actuators105 of may work on the pump piston 115, the compliant element 520, orother suitable surface to provide added power, force, and displacement.As a non-limiting example, a plurality of the solid-state actuators 105on the order of thousands, tens of thousands, or more, may work inconjunction on one or more suitable surfaces, and, for example, may beon a nanometric scale. Additionally, certain embodiments may beimplemented in medical applications, with, for example, the solid-stateactuators 105 configured to mimic the peristaltic motion of theesophagus, the motion of the diaphragm, bowels, heart, etc.

Therefore, the present disclosure is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent disclosure may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered ormodified and all such variations are considered within the scope andspirit of the present disclosure. Also, the terms in the claims havetheir plain, ordinary meaning unless otherwise explicitly and clearlydefined by the patentee. The indefinite articles “a” or “an,” as used inthe claims, are defined herein to mean one or more than one of theelement that that a particular article introduces; and subsequent use ofthe definite article “the” is not intended to negate that meaning.

1. A hydraulic pump comprising: a port; a piston assembly fluidicallycoupled to the port, wherein the piston assembly comprises: a piston;and a solid-state actuator, wherein a shape change of the solid-stateactuator is induced when a field is applied to the solid-state actuator,and wherein alternating shape changes of the solid-state actuatorprovide reciprocating movement to the piston.
 2. The hydraulic pump ofclaim 1, wherein the field is a magnetic field.
 3. The hydraulic pump ofclaim 1, wherein the field is an electric field.
 4. The hydraulic pumpof claim 1, wherein the port comprises an inlet or an outlet.
 5. Thehydraulic pump of claim 1, wherein the solid-state actuator comprisesone or both of a magnetostrictive material and a piezoelectric material.6. The hydraulic pump of claim 1, wherein the piston assembly furthercomprises: a coil disposed about the solid-state actuator to apply thefield to the solid-state actuator.
 7. The hydraulic pump of claim 1,further comprising an inlet valve and an outlet valve to rectify fluidflow through the port.
 8. The hydraulic pump of claim 1, furthercomprising an inlet valve and an outlet valve fluidically coupled to thepiston to facilitate a steady flow passage.
 9. The hydraulic pump ofclaim 1, wherein the solid-state actuator comprises a stack of platesconnected in parallel, wherein the plates comprise piezoelectricmaterial or magnetostrictive material.
 10. The hydraulic pump of claim1, wherein the piston assembly is part of an arrangement of pistonassemblies to be driven together.
 11. The hydraulic pump of claim 10,wherein the arrangement of piston assemblies is to be driven inparallel.
 12. The hydraulic pump of claim 10, wherein the arrangement ofpiston assemblies is to be driven in series.
 13. The hydraulic pump ofclaim 1, wherein the piston assembly further comprises a seal disposedbetween the piston and a cylinder to allow the piston to sealinglyreciprocate within the cylinder.
 14. A method of pumping fluid with ahydraulic pump comprising a solid-state actuator, the method comprising:providing a hydraulic pump comprising: a port; and a piston assemblyfluidically coupled to the port, wherein the piston assembly comprises:a piston; and a solid-state actuator, wherein a shape change of thesolid-state actuator is induced when a field is applied to thesolid-state actuator, and wherein alternating shape changes of thesolid-state actuator provide reciprocating movement to the piston;applying a varying field to the solid-state actuator to induce theseries of shape changes of the solid-state actuator and provide thereciprocating movement to the piston; and displacing at least a portionof a fluid through the port.
 15. The method of claim 14, furthercomprising: fluidically coupling the hydraulic pump to a radiator toreceive pumped fluid from the hydraulic pump, wherein the radiatortransfers heat from the pumped fluid to an exterior area adjacent to theradiator.
 16. The method of claim 15, further comprising: fluidicallycoupling the hydraulic pump to a closed-loop conduit assembly, whereinat least a portion of the closed-loop conduit assembly is proximate to aheat source.
 17. The method of claim 14, wherein the field is a magneticfield.
 18. The method of claim 14, wherein the field is an electricfield.
 19. The method of claim 14, wherein the solid-state actuatorcomprises a magnetostrictive material.
 20. The method of claim 14,wherein the solid-state actuator comprises a piezoelectric material.